Question

cho a+b+c=x+y+z=a/x+b/y+c/z=0 chưng  minh ẫng^2+by^2+cz^2=0 

Answer 1

Ta có \(\dfrac{a}{x}+\dfrac{b}{y}+\dfrac{c}{z}=0\Leftrightarrow ayz+bzx+cxy=0\).

Do đó: \(ax^2+by^2+cz^2=\left(ax+by+cz\right)\left(x+y+z\right)-\left(axy+axz+byz+byx+czx+czy\right)=0-xy\left(a+b\right)-yz\left(b+c\right)-zx\left(c+a\right)=xyc+yza+zxb=0\). (Do x + y + z = 0 và a + b + c = 0).

Answer 2

dễ hiểu thế mà ddoof N---------------------------------------------------------------------------------------------------------g----------------------------------------------------------------------------------------------u